If you go to the Toyota Tech Archive section, open up the lower left window to 'view all', and you'll find our old stuff on this subject.

On a front oil leak, if the front main is bad, it'll start leaking from behind the dust cover just aft of the crank pulley. Cleaning it up isn't a waste of time, as a clean engine disperses heat better. Yes, this can be changed w/o taking off the timing cover. <img src="/forums/images/graemlins/kewl.gif" alt="" />

On the coolant, there's a few things you can do passively:
* check the plugs. White usually indicates coolant
* Pressure test the cooling system
* Gases check cooling system-- kit at NAPA. Follow directions
* Leakdown test checks the top end, compression check is for the rings. Adjacent low numbers with a compression check generally point to a HG, but you'd follow up with a leakdown to make sure.
* If you KNOW it's leaking, there's one more check. Get some clean cardboard and lay it under the truck after you've had it running, right up to the firewall. Look for drips and follow upward.
* Get some coolant detector from NAPA and rent a black light. Add to coolant. Run engine while shining light around; leak will show up as flourescent green.

This will not hurt your cooling system. They also make one for oil, so pay attention to which one you grab, as the bottles look similar.

Go from there.